There is a need in the art to develop effective and useful non-destructive methods for testing various materials, as for example, pultruded stock material. Test methods in the prior art used sonic, ultrasonic and modal (non-destructive) analysis, as well as, four-point bending and short beam shear (destructive) mechanical tests.
However, there were problems with the aforementioned non-destructive methods. First, they were principally detecting fiber dominated properties. Consequently, the matrix dominated properties, which reflect more fully the influence of processing were being monitored secondarily. Second, implementation of the non-destructive methods was complicated by factors that included the following: non-uniform (three-dimensional) temperature gradients, noise-affected signals (e.g., electrical machinery and vibration from equipment), and the problem of sustainable boundary conditions on the ends of sampled pultruded specimens. Collectively, these influences provided only a marginal determination of property variation. Once error bounds were applied, differentiation due to processing become particularly difficult to assert with confidence.
The herein disclosed invention seeks to eliminate problems encountered by prior art test methods.